Field of the Invention
The present invention relates to an image capturing apparatus and a method for controlling the image capturing apparatus.
Description of the Related Art
Light that a human can perceive is, in general, light in the range from approximately 400 nm to approximately 680 nm (hereinafter, “visible light range”). Conventionally, in an image capturing apparatus such as a digital camera or a digital video camera, a filter for removing light in the ultraviolet light range up to 400 nm, a filter for removing light in the infrared light range from 680 nm, or the like is arranged in front of an image sensor for image capturing, in order to take in only the light in the aforementioned visible light range.
On the other hand, there is also a desire to detect infrared light in order to perform light source determination in an image capturing apparatus. For example, in Japanese Patent Laid-Open No. 2012-10282, the type of a light source is determined from an image containing light in the visible light range and in the infrared light range, and shooting conditions are controlled in accordance with the type of the light source.
Also, Japanese Patent Laid-Open No. 2002-202541 discloses a configuration in which two light-receiving elements sensitive to a wavelength band including the infrared light range and the visible light range are arranged in a photometric sensor in a single-lens reflex camera, and a visible light cut filter is arranged in an incident light region of one of the light receiving elements. Infrared remote control reception and light source determination are performed using the output from a light-receiving surface on which the visible light cut filter is arranged. The output corresponding to that of a light-receiving surface sensitive only to the visible light range can also be obtained by obtaining a difference between outputs of the two light-receiving surfaces. By performing photometry using these visible light range components, a photometric result can be brought closer to spectral characteristics of the image sensor.
However, if the conventional techniques disclosed in the aforementioned documents are to be used in a specific color detection sensor in a single-lens reflex camera, the following problem will arise.
In the case of detecting a specific color such as a flesh color, a plurality of color filters having different spectral transmittances in the visible light range are necessary. This is because if the color filters are sensitive to the infrared light range as well as the visible light range, the hue shifts when the color filters are in sunlight that radiates infrared light and when under an artificial light source such as an LED that does not radiate infrared light.
In the technique disclosed in Japanese Patent Laid-Open No. 2012-10282, an imaging apparatus is also sensitive to the infrared light range in order to perform light source determination processing. For this reason, if a plurality of color filters having different spectral transmittances within the visible light range cannot be provided, specific color detection processing cannot be performed.
With the technique disclosed in Japanese Patent Laid-Open No. 2002-202541, the output corresponding to that of a light-receiving surface sensitive only to the visible light range can be obtained by obtaining a difference between outputs of the two light-receiving surfaces, but a plurality of color filters having different spectral transmittances within the visible light range are not provided, and therefore specific color detection processing cannot be performed.
From another viewpoint, it is desired to detect infrared light in order to suppress a focus shift caused due to the type of a light source in an image capturing apparatus. For example, in Japanese Patent Laid-Open No. 2006-98771, a wavelength component detection sensor for detecting the visible light range and the infrared light range is arranged, and a defocus amount detected by a focus detection sensor is corrected in accordance with a difference between two outputs.
However, if the sensor disclosed in Japanese Patent Laid-Open No. 2006-98771 is to be used as a photometric sensor in a single-lens reflex camera, the following problem will arise.
In the technique disclosed in Japanese Patent Laid-Open No. 2006-98771, sensitive to the infrared light range is used. For this reason, if exposure amount determination computation for a photographic sensor is performed using the aforementioned sensor, a shift occurs in a photometric result due to a sensitivity difference in the infrared light range between the sensors.